high purge volume sub-slab samplinghigh purge volume sub-slab sampling • provides more information...

High Purge VolumeHigh Purge Volume SubSub--Slab SamplingSlab SamplingFormer Paragon Electric

Two Rivers, Manitowoc CountyPart III, Case Study

Annette Weissbach, WDNR-Green BayWisconsin’s Vapor Intrusion Guidance

FET – March 2011

Lake Michigan

Two Rivers

to Manitowoc

Paragon Electric

~27 acres

History• Manufacturer of electrical components (motors,

timers, switches). Property vacant/mothballed since the late 1990s. TCE used as parts cleaner until 1991, Investigation began 1985, continued through 2000s

• Soils: 40 feet fine sand, 1-5 feet clay, fine sand 15+ feet, Silurian bedrock ~90 feet

• Groundwater 7-14 feet below grade• 1993-2002 Source Remedy: soil vapor

extraction with groundwater sparging (ceased in 93), and groundwater extraction.

• Estimated 1600 pounds (~ 123 gallons) of TCE removed.

History

• 2006: Conditional closure granted w/GIS registry: soil and groundwater

• 2008: TA request for “clean” closure options

• 2008: joined the VPLE process• 2009-2010: Phase I/Phase II• 2009: VI Survey

Paragon Electric successive plumes

(guesstimated!)

High Purge Volume Sub-Slab Sampling

• Provides more information by removing a larger volume of soil gas

• Removes soil gas at a consistent rate, 25 to 100 scfm for a period of up to two hours.

• Removes sufficient volume of gas from a 6-inch gravel layer (30% porosity) to withdraw all soil gas within a radius of 25-50 feet.

• Concentration of extracted vapors monitored as a function of time

High Purge Volume Sub-Slab Sampling

• Field screening with slip-stream samples • Communication test points (CTP)• Applied vacuum measurements• Gas velocity measurements• Smoke tests (for leakage)• 6-liter summa canister for 30-100 minutes• Transient response tests

Former hazardous waste storage area Former TCE Vault area

Mini HPV test on former SVE well

Todd A. McAlary, M.Sc., P.Eng., P.G.

Practice Leader - Vapor Intrusion

Geosyntec Consultants, Inc.

130 Research Lane, Suite 2

Guelph, Ontario

N1G 5G3

(519) 822-2230 ext 239

Fax (519) 822-3151

Cell (905) 339-7066

tmcalary@geosyntec.com